Methods and systems for operating a vehicle driveline

Abstract

Systems and methods for improving operation of a hybrid vehicle are presented. In one example, an engine is accelerated to a speed of a driveline integrated starter / generator before the engine is coupled to the driveline integrated starter / generator.

Description

RELATED APPLICATIONS[0001]The present application claims priority to U.S. of America Provisional Patent Application 61 / 643,160 filed on May 4, 2012, the entire contents of which are hereby incorporated by reference for all purposes.FIELD[0002]The present description relates to a system and methods for improving drivability and fuel economy of a vehicle. The methods may be particularly useful for engines that are selectively coupled to an electrical machine and a transmission.BACKGROUND AND SUMMARY[0003]A hybrid vehicle may be provided with a driveline disconnect clutch. The driveline disconnect clutch may be closed to couple an engine with an electric machine. The driveline disconnect clutch may be opened to decouple the engine from the electric machine. The engine may provide torque to the driveline when the driveline disconnect clutch is closed. The engine is stopped when the driveline disconnect clutch is open to conserve fuel. However, starting the engine and coupling the engine...

AI Technical Summary

Benefits of technology

The patent text describes a method to reduce torque disturbances in a vehicle's driveline when the driver demands more torque, by quickly increasing the engine speed and closing a disconnect clutch to reduce the torque disturbance. This approach improves the response of the vehicle's driveline and reduces the chance of torque disturbances during driver demand.

Problems solved by technology

However, starting the engine and coupling the engine to the driveline may result in one or more driveline torque disturbances which may be objectionable to a driver.

Further, the approach may reduce the possibility of driveline torque disturbances.

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